STP port disable

Answered Question
Apr 8th, 2009

Is it possible to keep a particular port (access or trunk) out of the spanning tree even though STP is enabled on the VLAN that the port belongs to? If so, how?

I would like to have no control protocols enabled on a particular NNI, and I can do this on other non-cisco switches.

I have this problem too.
0 votes
Correct Answer by Jon Marshall about 7 years 6 months ago

You can effectively disable STP for a port if you use the "spanning-tree bpdufilter.." command - see attached link


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Tshi M Wed, 04/08/2009 - 06:03

when an access port is configured with span portf, that port no longer participate in the STP.


glen.grant Wed, 04/08/2009 - 06:07

That is incorrect , spantree portfast does not turn off spanning tree it just eliminates a couple of the spanning tree states so the port comes active faster, spanning tree is still running on that port...

viyuan700 Wed, 04/08/2009 - 06:49

On access port if you define portfast & bpduguard.

Port will be disabled if it gets BPDU means tries to take part in STP.

kraptor123 Wed, 04/08/2009 - 08:46

The spanning-tree bpdufilter seemed the best option to me, because the port never actually gets to the disabled/blocked state. Thanks for your help.

Here are some details I found on a different site -

The "spanning-tree bpdufilter enable" command on an interface is approximately equivalent to disabling the spanning tree for an interface.

BPDU filtering allows you to prevent a port from sending and receiving BPDUs. The configuration is applicable to the whole interface, whether it is trunking or not. This command has three states:

•spanning-tree bpdufilter enable-This state unconditionally enables the BPDU filter feature on the interface.

•spanning-tree bpdufilter disable-This state unconditionally disables the BPDU filter feature on the interface.

•no spanning-tree bpdufilter-This state enables the BPDU filter feature on the interface if the interface is in operational PortFast state and if the spanning-tree portfast bpdufilter default command is configured.

lamav Wed, 04/08/2009 - 09:46

Thanks for getting back to the board with that extra information.




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